A Chinese anthem played during a nationally televised gathering of senior Vietnamese officials this week has become fodder for online activists.

Senior officials, including President Truong Tan Sang and Defense Minister Phung Quang Thanh, gathered Monday at the Ministry of Defense to see a patriotic musical show.

But when Sang walked onto the stage to give the opening speech, the Chinese patriotic song "Ode to Motherland" played while a national audience watched from home.

The choice of a Chinese patriotic song is seen as an embarrassment for Vietnam, which has seen relations with Beijing sour in recent years over maritime disputes in the South China Sea.

"That mistake is not allowed to happen,” said Ha Kim Chi, head of inspection of the Vietnam Journalists Association. "The association of journalists will cooperate in joint meetings to manage our members. ... The state management bodies will decide the disciplines.”

The music in question has since been scrubbed from official Vietnamese websites and TV programs, but raw footage of the event has gone viral in Vietnam's online community.

Some speculated that the song was played by Chinese spies, while others said the issue was a matter of incompetence.

This show attracted public attention in the first place because of the reappearance of Thanh, who had been out of the public eye, leading to rumors about his health.

This report was produced in collaboration with the VOA Vietnamese service.